[Steve C.]

Adding this here for interest only, and note this statement... "if the port has been modified to support flow in this lift region".

Material published by David Vizard:

VALVE LIFT.
"A 2-valve cylinder head typically continues to flow more air up to lift values equal to as much as 0.35-0.4 times the valve diameter. The reason for this is that there is a flow pattern transition period that takes place at a lift value of about 0.25 of the valve's diameter. When this point is passed, if the port has been modified to support flow in this lift region, the valve efficiency actually starts to increase. This is the reason why a 2-valve engine responds to high lift." "If you want to build a street motor with the most power without a sacrifice of idle and low speed qualities, then lift is the most important factor to maximize, not duration. The best street cams are those that seek to maximize lift while only adding a minimal amount of duration."

Bottom line, the engine wants all the lift it can and thrives on it so run as much as mechanically achievable or prohibitive to you because of cost and/or budjet limitations (such as in a purchase for solid roller cam, longer valves to increase installed height, stronger springs, etc.). Obviously if it's a street application or race application will have a bearing on the situation, most here would be hesitant to run 0.700 lift on the street.



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